This is a code snippet that allows you to login to facebook via puppeteer.

index.js

const puppeteer = require('puppeteer');
const fs = require('fs');
const config = require('./config.json');
const cookies = require('./cookies.json');

(async () => {
  console.log('Hello World');
  //insert code here
  
  let browser = await puppeteer.launch({ headless: false });
  const context = browser.defaultBrowserContext();
  context.overridePermissions("https://www.facebook.com", []);
  let page = await browser.newPage();
  await page.setDefaultNavigationTimeout(100000);
  await page.setViewport({ width: 1200, height: 800 });
  
  if (!Object.keys(cookies).length) {
    await page.goto("https://www.facebook.com/login", { waitUntil: "networkidle2" });
    await page.type("#email", config.username, { delay: 30 })
    await page.type("#pass", config.password, { delay: 30 })
    await page.click("#loginbutton");
    await page.waitForNavigation({ waitUntil: "networkidle0" });
    await page.waitFor(15000);
    try {
      await page.waitFor('[data-click="profile_icon"]');
    } catch (err) {
      console.log("failed to login");
      process.exit(0);
    }
    let currentCookies = await page.cookies();
    fs.writeFileSync('./cookies.json', JSON.stringify(currentCookies));
  } else{
    //User Already Logged In
      await page.setCookie(...cookies);
      await page.goto("https://www.facebook.com/", { waitUntil: "networkidle2" });
  }
  
  //Close Browser
  //await browser.close(); 
})();